BackForwardInstrument:  ScaRaB 

Instrument details
Acronym ScaRaB
Full name Scanner for Radiation Budget
Purpose Earth radiation budget at Top Of Atmosphere (TOA)
Short description 4 channels, two broad-band, two narrow-band [see detailed characteristics below]
Background Developed in the French Laboratoire de Météorologie Dynamique
Scanning Technique Cross-track: 51 pixel/scan, swath 3300 km - Along-track: 1 scan / 6 s
Resolution 41 km IFOV
Coverage / Cycle Depending on the platform orbit. Near-polar: near-global daily; low inclination: 2 to 6 times/day depending on latitude (best coverage at 15°N and 15°S)
Mass 40 kg Power 42 W Data Rate 3 kbps


Providing Agency CNES
Instrument Maturity Backed by strong heritage
Utilization Period: 1994 to 1996
Last update: 2021-06-17
Detailed characteristics
Channel Spectral interval Noise Equivalent Radiance Absolute accuracy SNR
Short-wave 0.2 - 4.0 µm < 0.5 W m-2 sr-1 .......... W m-2 sr-1 850
Total radiance 0.2 - 50 µm < 0.5 W m-2 sr-1 .......... W m-2 sr-1 1000
VIS 0.55 - 0.65 µm < 1.0 W m-2 sr-1 .......... W m-2 sr-1 120
TIR 10.5 - 12.5 µm < 0.5 W m-2 sr-1 .......... W m-2 sr-1 60
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Earth observation instrument
  • Passive optical radiometer or spectrometer
  • Broadband Earth radiation radiometer
WIGOS Subcomponents
  • Subcomponent 1
  • Absolutely calibrated broadband radiometers, and TSI and SSI radiometers
Mission objectives
Primary mission objectives
  • Upward long-wave irradiance at TOA
  • Upward short-wave irradiance at TOA
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Tentative Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
VariableRelevance for measuring this variableOperational limitationsExplanation
Upward short-wave irradiance at TOA2 - very highInformation on BRDF needed.SW and Total (SW+LW) broadband channels, and supporting narrow-bandwidth channels for cloud detection
Upward long-wave irradiance at TOA2 - very highNo specific limitation.SW and Total (SW+LW) broadband channels with supporting narrow-bandwidth channel(s). LW computed as difference Total - SW